Filter

摘要

A filter comprises a spirally wound filter medium (10) formed of a corrugated filter layer (11) having valleys (13) and peaks (14) and a flat filter sheet (12). The valleys are connected to the flat filter sheet by a form-fit connection (15) or a welded connection, and alternately closed channels are formed between the peaks and the filter sheet. The form-fit connection is produced by embossing the filter layer and filter sheet together, such that indentations in the filter sheet or filter layer engage mating indentations in the filter layer or filter sheet, respectively.